1. Field of the Invention
The present invention generally relates to an optical apparatus which has a pair of optical systems and to a method for moving the pair of optical systems, and particularly relates to the optical apparatus which is preferably used for a stereoscopic camera, binoculars, etc., and to the method for moving the pair of optical systems along a pair of optical axes thereof.
2. Description of the Related Arts
Conventionally, there has been provided a stereoscopic camera, binoculars, or the like, as an optical apparatus, which has a pair of optical systems that are separate from each other. According to the conventional optical apparatus, one optical system thereof generally has a lens supporting mechanism for supporting a lens group, which is separate from a lens supporting mechanism of the other optical system thereof. That is, the lens supporting mechanism has a holder for holding the lens group, and members including a cam cylinder, a guide bar, etc. for guiding and moving the holder of the lens group, all arranged outside the lens group. Therefore, the lens supporting mechanism occupies a large radial space for mounting itself around the entire periphery of the lens group. Namely, the radial configuration of the lens supporting mechanism around the periphery of the lens group becomes large.
Meanwhile, in recent years, there has been a demand for supplying a thin type of video camera, or digital camera, which has a compact optical system and a compact lens supporting mechanism for supporting a lens group therein, accompanying a miniaturization of a photographing element, or an image taking element, in a field of the video camera or the digital camera.
However, the radial configuration of the conventional lens supporting mechanism around the periphery of the lens group is large. Therefore, it is difficult to make the lens supporting mechanism thinner as a whole.
On the other hand, a conventional stereoscopic camera generally has a pair of optical systems, for producing a pair of images of a subject, in which one of the optical systems is of the same type as that of the other thereof, and has a pair of image taking elements, for capturing the subject images of the subject which are gained by the pair of optical systems respectively, in which one of the image taking elements is of the same type as that of the other thereof.
The image captured by the one of the image taking elements is dislocated or deviated right and left from the image captured by the other thereof, because a direction in which the one of the image taking elements observes the subject is dislocated or deviated visually from a direction in which the other thereof observes the same subject. Due to this dislocation or deviation of the two images observed, a stereoscopic image is reproduced. Namely, a viewer can observe the subject stereoscopically, due to the dislocation or deviation of the subject images in the right and left direction.
From a physiological point of view, it is to be noted that a direction in which one eye of the viewer looks at an object is generally parallel with a direction in which the other eye of the viewer looks at the same object in case that the object is far away from the viewer, and that the directions are cast inward to each other in case that the object is not far away from the viewer.
The conventional stereoscopic camera, however, is generally so constructed that the pair of optical systems are oriented to each other at the same angle therebetween all the time. Therefore, for instance, there arises a problem that although the image of a distant subject gained when the viewer observes it gives him/her a natural three-dimensional effect, of the subject the image of a near subject gained when the viewer observes it gives him/her an unnatural three-dimensional effect thereof.
In order to solve this problem, it is possible to construct the two optical systems of the stereoscopic camera so that the relative orientation of the two optical systems thereof is changeable, depending upon a distance between the stereoscopic camera and the subject to be photographed or observed.
If, however, trying to design such optical systems, the optical systems become very complex; thus, it is impracticable.